College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China.
Environ Technol. 2013 Sep-Oct;34(17-20):2663-9. doi: 10.1080/09593330.2013.786103.
In this study, nanoscale zero-valent iron (NZVI) was synthesized by conventional liquid-phase chemical reduction methods without a support material and then characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The effect of NZVI particles on phosphate removal from aqueous solutions was examined. The results showed that the phosphate removal efficiency increased from 34.49% to 87.01% as the dosage of nanoscale iron particles increased from 100 to 600 mg L(-1) with an initial phosphate concentration of 10 mg L(-1), and the phosphate removal efficiency decreased from 72.89% to 51.39% as the initial phosphate concentration increased from 10 to 90 mg L(-1), with 400 mg L(-1) NZVI. Phosphate removal efficiencies of 99.41% and 95.09% were achieved at pH values of 2 and 4, respectively, with an initial phosphate concentration of 20 mg L(-1) and 400mg L(-1) NZVI. The use of NZVI particles synthesized in a carboxymethyl cellulose (CMC)-water solution significantly enhanced phosphate removal from an aqueous solution compared with the use of NZVI synthesized in an ethanol-water solution. NZVI particles achieved 71.34% phosphate removal, which was remarkably higher than that of microscale zero-valent iron (MZVI) particles (16.35%) with 10 mg L(-1) of phosphate and 400mg L(-1) iron. Based on the removal mechanism analysis performed in this study, we recommend that phosphate removal be accomplished by simultaneous adsorption and chemical precipitation. The XRD patterns of the NZVI before and after the reactions indicated the formation of crystalline vivianite (Fe3(PO4)2 x 8H2O) during the procedure.
在这项研究中，纳米零价铁（NZVI）通过传统的液相化学还原法合成，无需载体材料，然后通过透射电子显微镜（TEM）、扫描电子显微镜（SEM）和 X 射线衍射（XRD）进行表征。研究了 NZVI 颗粒对水溶液中磷酸盐的去除效果。结果表明，当初始磷酸盐浓度为 10mg/L 时，随着纳米铁颗粒用量从 100mg/L 增加到 600mg/L，磷酸盐去除效率从 34.49%增加到 87.01%，而当初始磷酸盐浓度从 10mg/L 增加到 90mg/L 时，磷酸盐去除效率从 72.89%下降到 51.39%，NZVI 的用量为 400mg/L。当初始磷酸盐浓度为 20mg/L 和 400mg/L NZVI 时，pH 值分别为 2 和 4 时，磷酸盐去除率分别达到 99.41%和 95.09%。与在乙醇-水溶液中合成的 NZVI 相比，在羧甲基纤维素（CMC）-水溶液中合成的 NZVI 颗粒显著提高了水溶液中磷酸盐的去除效率。NZVI 颗粒实现了 71.34%的磷酸盐去除率，显著高于 10mg/L 磷酸盐和 400mg/L 铁的微尺度零价铁（MZVI）颗粒（16.35%）。根据本研究进行的去除机制分析，我们建议通过同时吸附和化学沉淀来去除磷酸盐。反应前后 NZVI 的 XRD 图谱表明，在反应过程中形成了结晶磷铁石（Fe3(PO4)2 x 8H2O）。
